Production die



June 23, 1964 G. L. ANDERsEN PRODUCTION DIE 2 Sheets-Sheet 1 Filed March7, 1960 lo INVENTOR.

GEORGE L.ANDERSEN TTORNEYS June 23, 1964 G. L. ANDERSEN PRODUCTION DIE 2Sheets-Sheet 2 Filed March '7. 1960 1 INVENTOR.

RGE L AN DER SEN l @MSM/??? 57%? A ORNYS United States Patent()3,138,257 PRDUCHN DE l George lL. Andersen, Birmingham, Mich., assigner,by mesne assignments, to Avis industrial Corporation, Roseville, Mich.,a corporation of Michigan l Fiied Mar. 7, 196i), Ser. No. 13,159 l 14Claims. (Ci. 267m@ The present invention relates to improvements in aproduction die for the cold forming of hollow and like shaped metalparts. l

It is an object of the invention to provide die structure l Y adapted tobe engaged ilatwise by the die unit as the latter is advanced downwardlyby an upper die shoe and bolster assembly, and a fixed leveler plateguide and restraining unit, onto which a tubular bottom extension orsleeve of the leveler plate is axially telescoped with a n very closeand accurate clearance.

Another object is to provide production die structure of the sortdescribed, in which a novel die unit composed of an accurately formeddie insert, reinforced and coniined by surrounding shrink rings, isreleasably coupled to the upper die shoe unit by an improved form ofslack coupling.

Another object is to provide die structure of this sort, in which theupper die unit includes a tubular insert transmitting axial force to theformed die insert of the die unit, this insert being driven downwardlyby an upper die shoe which engages it at a spheroidal meeting surface sothat self aligning action as between the die-driving insert and theupper die shoe unit takes place closely adjacent the die parts, ratherthan remote from the same, as in previous structures of a generallycomparable nature.

A further object, in regard to the die aligning and level unit referredto above, is to provide means whereby the leveler plate of this unit isbrought to a position in which it is iiush with the top of a worktransfer plane, as well as the top of a stationary punch which coactswith the die, at the commencement of the forming operation, when a metalslug or blank is positioned coaxially above the punch. This isaccomplished by subjecting the leveler plate to a moderate pneumaticpressure to force the same upwardly, with means to engage a transferplate of the equipment to limit its movement to the said ush position.

A further important object of the invention is to provide, inassociation with the upper die shoe and bolster of the structure, animproved pneumatic shock absorber arrangement involving the trapping ofair under pressure between coaxial, horizontally spaced rings ofincompressible but elastically deformable material, as the upper bolsteroperates and engages the upper die shoe, This shock absorber actionadords a nearly constant acceleration of the motion of the upper diestructure as the rings are elastically forced in the radial directioninto the `space therebetween.l

Generally, it is an object to provide an improved production die which,by reason of the improved, accurately guided and aligned leveler plateaction, eliminates the need to lengthen the fixed punch of the die inorder to provide for the proper locating of the work piece or slugrelative to the die, coupled with the confining and bracing action ofshrink rings on the shaped die insert, enables the punch 3,138,257Patented June 23, 1964 ICC and die insert to be formed of less expensivematerials than has heretofore been possible. l

The foregoing as well as other objects will become more apparent asthisdescription proceeds, especially when considered in connection withthe accompanying drawings illustrating preferred embodiments of theinvention, wherein:

FIG. l is a fragmentary view in vertical axial section through aproduction die in accordance with theinvention, as the die is normallyassembled with other die forming assemblies (not shown), illustratingpunch and die parts and their positional relationship at the time thecold forming of a metal object is completed; and

FiGS. 2 and 3 are fragmentary views in section similar to FIG. 1,respectively showing the parts at the commenoement of the cold formingoperation and at an intermediate stage in the operation.V

Referring to FIG. l, the die structure in general comprises a lower dieshoe bolster 1li, upon which a lower die shoe il is mounted in aconventional manner; a stationary punch and Aalignment sub-assembly,generally designated 12.; a leveler plate sub-assembly, generallydesignated 13 which coaxially telescopes accurately on `a part of thealignment sub-assembly 12; a die unit or sub-assembly 14, includingslack coupling provisions to be described; an upper die shoe assembly15; and an upper die shoe bolster 16, by which the die shoe 15 is driventhrough improved pneumatic shock absorber provisions, to be described.

The lower bolster l@ is, in conventional manner, formed to provide ahydraulic cylinder 18, to which hydraulic pressure liquid may besupplied, as through a conduit 19 at its bottom, at a relativelymoderate pressure of, say 40 pounds per square inch, or a relativelyhigh pressure of about 2000 pounds per square inch, under the control ofsuitable valve provisions (not shown) A sealed piston 20 worksvertically in cylinder 18 under thispressure, its plunger 2i beingguided adjacent the top of bolster 10 and projecting thereabove, Plunger2l engages beneath the center of a three-armed spider 22, the arms ofwhich in turn engage beneath three knockout or stripper pins 23. Thesepins are guided for vertical action in bores 24 of a stationary punchback-up plate or block 25 of the alignment unit or sub-assembly 12, andtheir action will be hereinafter referred to. The spider 22 isvertically guided in the lower die shoe 11, preferably in acorrespondingly shaped opening or bore 26 opening through the die shoe.

The alignment unit 12 comprises a cylindrical alignnient tube 27, whichis supported on the top of die shoe 11 and is fixed accurately inrelation to the latter by means of an annular locator plate 2.8 doweledinto the die shoe. The alignment tube Z7 is further confined adjacentits top in an opening in a fixed horizontaltransfer plate 29 lof theequipment.

Alignment unit or sub-assembly 12 further comprises a cylindricaltubular leveler plate guide 31, mounted on the back-up plate or block25, coaxially of the lower hydraulic cylinder i8. Guide 31 is ofconsiderable length along its upright axis to provide a stable guidingaction for the leveler plate unit 13 in a manner to be described; and itis braced adjacent its bottom within the alignment tube 27' by a fixedhorizontal platform 32. Platform 32 is provided with one or moreopenings therethrough, as

indicated at 33, and the annular space surrounding the back-up plate 25may serve as a manifold through which compressed air at a mild pressureof about 20 pounds per square inch is supplied to the annular spacebetween alignment tube 27 and the tubular leveler plate guide 31, for apurpose to be described. l

lt is to be noted that the upper extremity of alignment tube 27 isformed to provide a radially inwardly extending annular shoulder 35 forupwardly limiting the motion of the leveler plate unit 13, for a purposealso to be described. Otherwise, the parts of the fixed tubularalignment sub-assembly 12 are shouldered, for example as indicated at36, to constitute the same a functionally unitary structure.

The leveler plate assembly or unit 13 comprises a horizontal flatleveler plate 38 of circular outline having a cylindrical, axiallyelongated annular guide sleeve 39 welded or otherwise secured independent relation to its bottom surfaces, in centered relation to theplate 38. The sleeve 39 has a close tolerance axially telescopingengagement about the tubular leveler plate guide 31, and overlaps thesame a distance in an axial direction, as the parts slide axiallyrelative to one another, which approximates or is substantially of theorder of their diameter at the sliding surfaces. A suitable seal 40 isprovided between these parts, and it will be appreciated that theleveler plate unit 13 is thereby guided in its vertical movement withaccuracy and stability, due to the close tolerance lit and long axialoverlap of sleeve 39 and guide 31.

Leveler plate 38 is provided with an axial bore 42 therethrough; and anannular sealing ring 43 is peripherally welded about the bottom of plate38, this seal encircling the inner wall of the fixed alignment tube 27and thus further assisting in guiding plate unit 13 in the latter. Afurther function of the sealing ring is to upwardly engage against theshoulder 35 of the alignment tube 27 and thereby limit upward movementof plate 38 to a position in which its top surface is ush with that ofthe -alignment tube and the transfer plate 29 in which the alignmenttube is received. See FIG. 2.

The reference numeral 45 generally designates the fixed upright punch ofthe die structure. It is, of course, shaped in accordance with the crosssection of the hollow or cup-shaped product P to be produced, which maybe assumed to be cylindrical, so that the punch 45 is therefore of thiscross sectional outline. It is shown as being of diminished diameter atits upper portion 46. Punch 45 is bottomed upon the back-up plate 25,and is conned in place by a punch retainer block 47, through bores inwhich the stripper pins 23 extend.

The inner wall of the leveler plate guide sleeve 31 serves to guide anouter punch guide or stripper member 49, which has a close sliding twith the larger diameter portion of punch 45. Its lower portion 50 isfrustoconical, from which portion it extends upwardly in a cylindricalcross section at 51, which section is machined for relatively closesliding t in the bore 42 of the leveler plate 38 when stripper 49 iselevated as shown in solid line in FIG. 2. It is elevated to thisposition, to which it is limited by engagement of its frusto-conicalbottom 50 with a mating surface 52 at the top of tubular guide 31, bythe moderate pressure of about 40 pounds per square inch in hydrauliccylinder 1S mentioned above. This is done through the agency of thespider 22 and stripper pins 23. The product P is stripped ultimatelyfrom punch 45 under the aforementioned hydraulic pressure of 2000 poundsper square inch on piston or plunger in cylinder 1S. The product issimilarly stripped from an upper die insert (to be described) under acorresponding downward hydraulic force exerted in the upper die shoe andbolster units 15, 16, aswill be described.

The moving die unit 14 comprises a central die insert 53 of tungstencarbide or high speed steel which is internally shaped in an invertedcup-like cross section, in accordance with the desired shape of theultimate product P. Insert 53 has an axial clearance opening or bore 54through its top, and is externally of slightly upwardly and outwardlytapered, circular outline. An inner, relatively thick shrink ring 55surrounds the insert 53, having a correspondingly tapered and matinginner perimeter, the insert and inner shrink ring 55 having a driven tat these slightly tapered surfaces. An outer shrink ring 56 surroundsand has a shrink t about inner ring 55, the

'outer shrink ring having a sliding t in the top opening 57 of alignmenttube 27 of alignment sub-assembly 12, above the shoulder 35 of thattube.

The die unit 14 has affixed thereto, and actually serving as a partthereof, an annular slack coupling device, generally designated 5S. Thismay consist of an annular plate or disk 59 secured by bolts 60 or thelike to the outer shrink ring 56 of the die unit, and an upstandingcylindrical wall 61 welded about disk 59. The latter has an axial innerbore 62, for a purpose to be described. The slack coupling wall 61 isprovided at its top with an inwardly directed, bayonet type connectingshoulder 63, through the agency of which the couplingV assembly 58 anddie unit 14 may be lifted upon upward retraction of the upper die shoeassembly 15.

The upper die shoe assembly includes a steel upper die shoe proper 65having a central bore 66 coaxial with the other punch and die parts. Anarmular locating clamp 67 is bolted or otherwise secured, preferablyreleasably, to the lower surface of the die shoe 65, this clampsurrounding and serving as a mount for an inner bayonet type connectingring 68, to which it is welded or otherwise xedly secured. Ring 68 isexternally provided with a suitable bayonet type formation 69 forcoaction with the shoulder 63 of slack coupling 58 in elevating the dieunit 14 upon a retractile stroke of upper die shoe 65. The nature ofsuch releasable, bayonet-type provisions are well known and understoodby those skilled in the art, it being contemplated that a rotation ofthe coupling about the bayonet ring 68 will enable the coupling and dieunit 14 to be separated from the upper die shoe. This loose type ofconnection permits proper and desired alignment of the die shoe partswith the die unit 14 and connecting provisions, through self-aligningprovisions at the die components themselves, rather than at some remotelocation.

Bayonet ring 68 is also provided with an inwardly directed annularshoulder 71 about its bottom, for engagement with upper die parts onsuch retractile stroke, while permitting self alignment of such partswith the remaining die structure. These parts include a central annularanvil ring insert 72 which has a ring 73 surrounding and shrunk tthereto to constitute a unitary anvil device. Shrink ring 73 is providedwith an outwardly directed shoulder 74 for coaction with the inturnedshoulder 71 of the bayonet ring 68 i lifting the anvil device.

This type loose or slack coupling, as combined with the accurate andstable guiding of leveler plate 38 by sleeve 39 and guide 31 for a trueaxial movement at 90 to the press gibs, enables an improved selfalignment of force transmitting surfaces adjacent the die, thus topreserve a true axiality of force relative to punch 45, so that thelatter is not subjected to any transverse force at all tending to cantit in operating on the workpiece or slug. The surfaces include a mildlyspheroidal annular bottom surface 76 on the anvil ring insert 72,concave in nature and a mating convex spheroidal surface 77 on a tubularinsert support 78 coaxial therewith. This support 78 extends downwardlyinto the bore 62 of the plate or disk 59 of slack coupling 58, where ithas axial thrust transmitting engagement with the die insert 53 of dieunit 14, outwardly overlapping in the radial sense a corresponding areaof the inner shrink ring 55 of the die unit.

The anvil insert ring 72 also has mating thrust engagement with thecoaxial convex spheroidal surface 8i) of a two-piece knockout pin S1mounted for sliding movement within the bore of the insert support 78.This pin is constituted by a lower nose portion 82 which is received inthe upwardly opening bore 54 of die insert 53, being downwardly taperedfor this purpose, and an upper anvil portion 83 in tlatwise engagementwith the top of the nose portion 82 and having the anvil surface 80formed thereon.

The reference numeral 85 generally designates a knockout assembly,including a pin or plunger 86 slidably received in the bore 66 of upperdie shoe 65, and provided with an enlarged lower cylindrical portion 87which slides within the anvil insert ring 72. The portion 87 has aconcave spheroidal bottom surface 8S in mating and self-aligningengagement with the convex surface 80 of knockout pin 81.

At its upper end the plunger S6 carries a piston 39 of enlarged diameterwhich slides in a hydraulic cylinder 90 formed in the upper bolster 16.The top portion of cylinder 90 is adapted to be placed in communication,as through a conduit 91, with a source of hydraulic pressure which, asin the case of the hydraulic supply for the bottom cylinder 1S, may beselectively controlled through suitable pressure and flow controlvalveprovisions (not shown) to furnish a mild pressure of, say, 40pounds per square inch, for initially bringing the lower portion 87 ofknockout pin or plunger S5 to the position of FIGS. l and 2, or arelatively heavy pressure of about 2000 pounds per square inch for laterdownward stripping of the product P from the die insert 53.

The die structure is completed by provisions for affording a shockabsorber action at the upper bolster, which it will be understood isbolted or otherwise secured to the ram (not shown) of a press whose baseor platen is constituted by the lower bolster 10, and for thus enablinga nearlyl constant shock free acceleration in the downward cold formingphase of the operation of the upper die unit 14. To this end, the uppersurface of upper die shoe 65 is formed to provide an annular recess 93coaxially surrounding the axis of the die parts, the function of whichrecess is that of an annular pressure cylinder. Within the cylinderrecess there are disposed two concentric, inner and outer shock absorberrings 94, 95, respectively, with an annular expansion space 96 lefttherebetween. The rings 94, 95 are, in accordance with the invention,fabricated of polyurethane or like incompressible but elasticallydistortable material, so that upon mechanical axial compression theinner ring 94 may distort radially outwardly and expand toward the space96, the outer ring correspondingly distorting and expanding inwardlytoward this space. v

The bottom surface of the upper bolster 16 is provided with an annularpiston formation 93 which fits axially with a close radial toleranceinto the annular cylinder 93 of upper die shoe 65, when the parts are inoperative, force transmitting position. The bottom surface of pistonformation 93 engages flatwise the upper surface of the shock absorberrings 94, 95. It should be specially noted that an axial clearance space99 is left between the bottom youtwardly of the piston formation.. Thepurpose of this relationship will appear.

Upper die shoe 65 is further provided with a radial passage 102 openingupwardly into a chamber 103, in which a simple check valve 104 isdisposed. Die shoe 65 .is counterbored at 105 above the chamber 103 toreceive a fluid-permeable cover 166. The passage 102 is thuscommunicated for the one-way application of air pressure yto the annularspace 96 between shock absorber rings 94- and 95. The passage issuitably connected with a source of supply (not shown) of air at apressure of about S0 pounds per square inch, this pressure beingmaintained within the space 96 even when axial force is not beingvtransmitted to the die parts.

In operation, now referring to FIGS. 2 and 3 in conjunction with FIG. 1,it will be assumed that thev parts are in the neutral position shown inFIG. 2, with the leveler plate 38 of leveler unit 13 Hush with the uppersurface of `the transfer plate 29. It has been brought upwardly to thisposition by the application of a mild 20 p.s.i. pneumatic pressurethrough the passage 33 in the platform 32 of alignment unit 12, so thatthe leveler plate unit or sub-assembly 13, as accurately guided by the`sleeve 31 of the alignment unit 12, and by its sealing ring 43, iselevated to the FIG. 2 position. The engagement of the ring 43 with theshoulder 35 on alignment tube 27 stops the plate 33 in this accuratelyaligned and ilush position, It will be noted that in this position thetop of leveler plate 33 is also flush with the top of punch 45; and thatthe stripper member 49 surrounding the punch has also been elevated tothe same level, through the agency of the pins 23 therebeneath, thespider 22 and the piston 20, which is raised under the approximate 40p.s.i. hydraulic pressure in cylinder 13.

In this initial condition of FIG. 2, the die unit 14 is elevatedsubstantially above the plane of the transfer table and leveler plate38, in order to enable the metal blank or slug, designated S in FIG.2,*to be placed in position by the transfer mechanism (not shown). Theupper, twopart knockout pin S1 is at this time located within theforming recess of the die insert 53. The upper bolster 16, die shoe 65and bayonet connecting ring 68 are now lowered, lowering die unit 14through the connecting slack coupling 53.

The die insert 53 and shrink rings 55, 66 of die unit 14 contact theleveler plate 38 about 1/s inch in advance of the commencement offorming of the blank or slug S. Force applied to knockout pin 31 undermoderate, 40 p.s.i. pressure from above has brought the pin into thebore 54 of die insert 53, where it engages the top of the blank as shownin FIG. 3. During the actual forming operation under ram force, both theupper knockout pin 81 and the lower stripper member 49 remain under theoriginalpressure of but 40 p.s.i. The greater pressure of, say, 2000p.s.i. is later applied in stripping.

Two things happen as the die unit 14l descends, prior to the building upof true forming force between die insert 53, the slug S and the lixedpunch 45. The bottom surface of unit 14 comes into flush, latwiseengagement with thetop of leveler plate 38, and the outer shrink ring 56of die unit 14 pilots. telescopingly into the top of the fixed`alignment tube Z7.

K The rst of these almost simultaneously occurring actions results in atilting shift of the die unit, at the convex rounded surface 77 of thesupport 78 fixedly connected to the unit, relative to the concaverounded surface 76 of the anvil ring insert 72. Thus, should there be aneedfor it, the die unit 14 is corrected angularly by positive referenceto the stably guided leveler plate 3S, the mating rounded surfaces 76,77 sliding relatively and in continuing Contact with one another overtheir meeting areas.

The second action of the parts, inthe telescoping entry of shrink ring56 into alignment tube 27, results in a bodily lateral shift of unit 14in one direction or another i so that, if it is off-center, the unit 14and its die insert 53 are returned to true coaxiality with punch 45, thesurfaces 76, 77 maintaining their mated engagement. v The loosecouplings at coupling wall shoulder 63, ring formation 69 and shrinkring shoulder 74 freely permit these actions.

l As the upper bolster 16 descends under ram force, the tubular insertsupport 73 initially engaging die insert 53, the polyurethane shockIabsorber rings 94, in the cylinder 93 between 'the bolster and upperdie shoe 65 are axially compressed strongly, causing them to moveradially into the space 96, and developing up to 1500 p.s.i. cushioningpressure between the piston formation 98 and cylinder .93, which buildsup to 4000 p.s.i. pressure as the stroke progresses.

As mechanicalforce continues to be transmitted to die linsert 53 throughthe self-aligning anvil insert 72 and insert support 78, the metal ofthe slug S is caused to How downwardly into the axial and radial spacebetween the rigidly sustained lower punch 45l and the die insert 53,

as shown in FIG. 3, the stripper member 49` the while ananas? iftelescoping relation over the top portion l of stripper member 49 andover the tubular guide 3l, being sustained by the light hydraulicpressure therebeneath, and at this time forming is complete.

The upper ram-supported parts are now withdrawn and 2000 p.s.i.hydraulic pressure is applied to both the top and bottom cylinders 90,18, respectively, to strip the formed product from punch 45 and dieinsert 53.

Accurate self-alignment, through joint coaction of the leveler plate 38,the telescoped die unit 14, the mating spheroidal surfaces 76, 77, andthe loose action of the slack coupling 5S is made possible. A true axialforce is developed on each die stroke, once the force transmitting andforce receiving members initially become aligned, along the line of theaxis of fixed punch 45, by the long and stable guiding action exertedalong that line by plate 38 through its depending sleeve 39 and fixedtubular guide 31.

This combination of the accurately guided floating leveler plate 33,spheroidal thrust transmitting surfaces and slack coupling has theadvantages of permitting a very quick change of forming tools, ofenabling the equipment to handle an off-center extrusion with goodconcentricity, of transferring wear to the gibs which guide the movingpress part without effect on the operation of the tools, and of enablingefhcient operation in the event of non-parallel bolster plates.

Due to the different clearances between the upper bolster 16 and upperdie shoe 65, i.e., at 99 and 100, the desred pneumatic shock absorberaction is permitted to develop at the polyurethane rings 94, 95 prior tomechanical engagement of bolster with the die shoe 65 about itsperipheral zone at 100. Therefore, the die shoe may flex elastically anddevelop any required tonnage prior to and after such engagement. The airtrapped in the space between the polyurethane rings 94, 95 gives anearly constant axial acceleration as the rings distort into the space95 therebetween. A full load cushion is provided by the elastic materialfor normal loads, plus a flexing deformability of the die shoe in theevent of overload. High pressure shock is eliminated.

In this manner, shock loading is avoided, which permits the use of lowcobalt content (3% to 8%) tungsten carbide, as compared with the usuall6%-24% content, and permitting the development of 800,000 pounds persquare inch pressure.

The drawings and the foregoing specification constitute i a descriptionof the improved production die in such full, clar, concise and exactterms as to enable any person skilled in the art to practice theinvention, the scope of which is indicated by the appended claims.

What I Claim as my invention is:

l. Production die equipment comprising press force applying means, apair of coaxial, relatively movable die units engageable in the axialdirection thereof with a piece to be formed in a relative formingmovement of said units under force applied thereto by said means in saiddirection, one of said units having a rounded force receiving surface, aforce applying member having a rounded surface adapted for coaxialmating and selfaligning engagement with said first named rounded surfaceto exert forming force from the latter on said piece in said axialdirection, means providing a loose coupling connection of said pressforce applying means with said force applying member and said die unitcapable of permitting a tilting shift of said rounded surfaces relativeto and in mated engagement with one another, and of permitting a lateralshift of said die unit relative to said press force applying means, andmeans acting on said unit to produce said respective shifts through saidloose coupling connection at the outset of a forming stroke, said lastnamed means comprising a leveling surface having means rigidly guidingthe same for accurate axial movement along the axis of the other dieunit, said one die unit having a surface other than its rounded surfacewhich engages said leveling surface to occasion said relative tiltingshift at said rounded surfaces, and a fixed guide member slidinglyengaging said one die unit to occasion said relative lateral shift ofthe latter.

2. Production die equipment in accordance with claim l, in which saidloose coupling connection means includes means providing loose couplingsrespectively between said press force applying means and said forceapplying member, and between said force applying means and said one dieunit.

3. Production die equipment in accordance with claim 1, in which saidloose coupling connection means includcs means providing loose couplingsrespectively between said press force applying means and said forceapplying member, and between said force applying means and said one dieunit, the last named coupling being one enabling a ready separation ofsaid one die unit from said press force applying means by a simplerelative movement of the same other than the relative motion due to theloose coupling thereof.

4. Production die equipment in accordance with claim l, in which saidfixed guide member has an annular opening coaxial with said other dieunit and telescopingly receiving said one die unit with slidingclearance to maintain said die units coaxial in the forming stroke, saidleveling surface moving axially within said opening.

5. Production die equipment in accordance with claim l, in which saidfixed guide member has an annular opening coaxial with said other dieunit and telescopingly receiving said one die unit with slidingclearance t0 maintain said die units coaxial in the forming stroke, saidleveling surface moving axially within said opening.

6. Production die equipment in accordance with claim l, in which saidfixed guide member has an annular opening coaxial with said other dieunit and telescopingly receiving said one die unit with slidingclearance to maintain said die units coaxial in the forming stroke, saidleveling surface moving axially within said opening, said levelingsurface being provided with an elongated tubular sleeve element ofsubstantial length extending axially therefrom in the direction awayfrom said one die unit, and an axially elongated fixed guide elementexternally telescoped slidingly by said sleeve element over asubstantial axial length to guide said sleeve element and levelingsurface.

7. Production die equipment in accordance with claim 1, in which saidfixed guide member has an annular opening coaxial with said other dieunit and telescopingly receiving said one die unit with slidingclearance to maintain said die units coaxial in the forming stroke, saidleveling surface moving axially within said opening, said levelingsurface being provided with an elongated tubular sleeve element ofsubstantial length extending axially therefrom in the direction awayfrom said one die unit, and an axially elongated fixed guide elementexternally telescoped slidingly by said sleeve element over asubstantial axial length to guide said sleeve element and levelingsurface.

8. Production die equipment comprising press force applying means, apair of coaxial, relatively movable die units engageable in the axialdirection thereof with a piece to be formed in a relative formingmovement of said units under force applied thereto by said means in saiddirection, one of said units having a rounded force receiving surface, aforce applying member having a rounded surface adapted for coaxialmating and selfaligning engagement with said first named rounded surfaceto exert forming force from the latter on said piece in said axialdirection, means providing a loose coupling connection of said pressforce applying means with said force applying member and said die unitcapable of permitting a tilting shift of said rounded surfaces relativeto and in mated engagement with one another, and of permitting a lateralshift of said die unit relative to said press force applying means, andmeans acting on said unit to produce said respective shifts through saidloose coupling connection at theoutset of a forming stroke, said loosecoupling connection means including means providing loose couplingsrespectively'between said press force applying means and said forceapplying member, and between said force applying means and said one dieunit.

9. Production die equipment comprising press force applying means, apair of coaxial, relatively movable die units engageable in the axialdirection thereof with a piece to be formed in a relative formingmovement of said units under force applied thereto by said means in saiddirection, one of said units having a rounded force receiving surface, aforce applying member having a rounded surface adapted for coaxialmating and selfaligning engagement with said rst named rounded surfaceto exert forming force from the latter on said piece in said axialdirection, means providing a loose coupling connection of said pressforce applying means with said force applying member and said die unitcapable of permitting a tilting shift of said rounded surfaces relativeto and in mated engagement with one another, and of permitting a lateralshift of said die unit relative to said press force applying means, andmeans acting on said unit to produce said respective shifts through saidloose coupling connection at the outset of a forming stroke, said lastnamed means comprising a leveling surface having means `rigidly guidingthe same for accurate axial movement along the axis of the other dieunit, said one die unit having a surface other than its rounded surfacewhich engages said leveling surface to occasion said relative tiltingshift at said rounded surfaces, said loose coupling connection meansincluding means providing loose couplings respectively between saidpress force applying means and said force applying member, and betweensaid force applying means and said one die unit.

10. Production die equipment comprising press force applying means, apair of coaxial, relatively movable die units engageable in the axialdirection thereof with a piece to be formed in a relative formingmovement of said units under force applied thereto by said means in saiddirection, one of said units having a rounded force receiving surface, aforce applying member having a rounded surface adapted for coaxialmating and selfaligning engagement with said iirst named rounded surfaceto exert forming force from the latter on said piece in said axialdirection, means providing a loose coupling connection of said pressforce applying means with said force applying member and said die unitcapable of permitting a tilting shift of said rounded surfaces relativeto and in mated engagement with one another, and of permitting a lateralshift of said die unit relative to said press force applying means, andmeans acting on said unit to produce said respective shifts through saidloose coupling connection at the outset of a forming stroke, said lastnamed means comprising a lixed guide member slidingly engaging said onedie unit to occasion said relative lateral shift of the latter, saidloose coupling connection means including means providing loosecouplings respectively between said press force applying means and saidforce applying member, and between said force applying means and saidone die unit.

l1. Production die equipment comprising press force applying means, apair of coaxial, relatively movable die units engageable in the axialdirection thereof with a piece to be formed in a relative formingmovement of said units under force applied thereto by said means in saiddirection, one of said units having a rounded force receiving surface, aforce applying member having a rounded surface adapted for coaxialmating and self-aligning engagement With said rst named rounded surfaceto exert forming force from the latter on said piece in said axialdirection, means providing a loose coupling connection of said pressforce applying means with said force applying member and said die unitcapable of permitting a tilting shift 10 of said rounded surfacesrelative to and in mated engagement with one another, and of permittingAa lateral shift of said die unit relative to said press force applyingmeans, and means acting on said unit to produce said respective shiftsthrough said loose coupling connection at `the outset of a formingstroke, said loose coupling connection means including means providingloose couplings respectively between said press force applying means andsaid force applying member, and between said force applying means andsaid one die unit, the last named coupling being one enabling a readyseparation of said one die unit from said press force applying means bya simple relative movement of the same other than the relative motiondue to the loose coupling thereof.

12. Production die equipment comprising a pair of coaxial, relativelymovable die units engageable in an axial direction in the relativemovement thereof, one of said units comprising an axially movableforming member, means to apply forming pressure to said forming member,including a pair of pressure members engaging one another in an axialdirection, `a bolster to move one of said pressure members axially, andmeans providing a fluid pressure shock absorbing and force transmittingconnection between said bolster andthe last named pressure member,including axially telescoping piston and cylinder means connectedrespectivley to the latter and the bolster, and a pair of concentricelastically deformable rings spaced radially from one another in saidcylinder means and engaged in an axial'direction and compressed by thecylinder means.

13. Production die equipment comprising a pair of coaxial, vrelativelymovable die units engageable in an axial direction in the relativemovement thereof, one of said units comprising an axially movableforming member, means to apply forming pressure to said forming member,including a pair of pressure members engaging one another in an axialdirection and having coaxial mating, engaging and self-aligning roundedsurfaces, a bolster to move one of said pressure members axially, andlost motion means providing a fluid pressure shock absorbing and forcetransmitting connection between said bolster and the last named pressuremember, including axially telescoping piston and cylinder meansconnected respectively to the latter and the bolster, a pair ofconcentric elastically deformable rings spaced radially from one anotherin said cylinder means and engaged in an axial direction and compressedby the cylinder means, and a lost motion connection between said onepressure member and said bolster to permit self-aligning of saidpressure members at said surfaces for the transmission of truly axialforce to said die units.

14. Production die equipment comprising a pair of co-` axial, relativelymovable die units engageable in an axial direction in the relativemovement thereof, one of said units comprising an axially movableforming member, means to apply forming pressure to said forming member,including a pair of pressure members engaging one another in an axialdirection and having coaxial mating, engaging and self-aligning roundedsurfaces, a bolster to move one of said pressure members axially, andlost motion means providing a iluid pressure shock absorbing and forcetransmitting connection between said bolster and the last named pressuremember, including axially telescoping piston and cylinder meansconnected respectively to the latter and the bolster, a pair ofconcentric elastically deformable rings spaced radially from one anotherin said cylinder means and engaged in an axial direction and compressedby the cylinder means, and a lost motion connection between said onepressure member and said bolster to permit self-aligning of saidpressure members at said surfaces for the transmission of truly axialforce to said die units, one of said die units having a readilyreleasable connection to said bolster in addition to said lost motionconnection.

(References on following page) UNITED STATES PATENTS Quimby Dec. 12,1899 Lyman June 8, 1926 Horak Sept. 24, 1929 Mantle Aug. 18, 1931 FridenJune 20, 1939 12 Ernst Oct. 29, 1940 Maude Oct. 27, 1942 Lorant Mar. 13,1945 Lerma Sept. 20, 1949 Schweller Feb. 10, 1953 Lefere Sept. 3, 1957Braun et al Sept. 15, 1959

1. PRODUCTION DIE EQUIPMENT COMPRISING PRESS FORCE APPLYING MEANS, APAIR OF COAXIAL, RELATIVELY MOVABLE DIE UNITS ENGAGEABLE IN THE AXIALDIRECTION THEREOF WITH A PIECE TO BE FORMED IN A RELATIVE FORMINGMOVEMENT OF SAID UNITS UNDER FORCE APPLIED THERETO BY SAID MEANS IN SAIDDIRECTION, ONE OF SAID UNITS HAVING A ROUNDED FORCE RECEIVING SURFACE, AFORCE APPLYING MEMBER HAVING A ROUNDED SURFACE ADAPTED FOR COAXIALMATING AND SELFALIGNING ENGAGEMENT WITH SAID FIRST NAMED ROUNDED SURFACETO EXERT FORMING FORCE FROM THE LATTER ON SAID PIECE IN SAID AXIALDIRECTION, MEANS PROVIDING A LOOSE COUPLING CONNECTION OF SAID PRESSFORCE APPLYING MEANS WITH SAID FORCE APPLYING MEMBER AND SAID DIE UNITCAPABLE OF PERMITTING A TILTING SHIFT OF SAID ROUNDED SURFACES RELATIVETO AND IN MATED ENGAGEMENT WITH ONE ANOTHER, AND OF PERMITTING A LATERALSHIFT OF SAID DIE UNIT RELATIVE TO SAID PRESS FORCE APPLYING MEANS, ANDMEANS ACTING ON SAID UNIT TO PRODUCE SAID RESPECTIVE SHIFTS THROUGH SAID